Large Interferometer For Exoplanets (LIFE): XIII. The Value of Combining Thermal Emission and Reflected Light for the Characterization of Earth Twins

Abstract

Following the recommendations to NASA and ESA, the search for life on exoplanets will be a priority in the next decades. Two direct imaging space mission concepts are being developed: the Habitable Worlds Observatory (HWO) and the Large Interferometer for Exoplanets (LIFE). HWO focuses on reflected light spectra in the ultraviolet/visible/near-infrared (UV/VIS/NIR), while LIFE captures the mid-infrared (MIR) emission of temperate exoplanets. We assess the potential of HWO and LIFE in characterizing a cloud-free Earth twin orbiting a Sun-like star at 10 pc, both separately and synergistically, aiming to quantify the increase in information from joint atmospheric retrievals on a habitable planet. We perform Bayesian retrievals on simulated data from an HWO-like and a LIFE-like mission separately, then jointly, considering the baseline spectral resolutions currently assumed for these concepts and using two increasingly complex noise simulations. HWO would constrain H${}_2$O, O${}_2$, and O${}_3$, in the atmosphere, with ~ 100 K uncertainty on the temperature profile. LIFE would constrain CO${}_2$, H${}_2$O, O${}_3$ and provide constraints on the thermal atmospheric structure and surface temperature (~ 10 K uncertainty). Both missions would provide an upper limit on CH${}_4$. Joint retrievals on HWO and LIFE data would accurately define the atmospheric thermal profile and planetary parameters, decisively constrain CO${}_2$, H${}_2$O, O${}_2$, and O${}_3$, and weakly constrain CO and CH${}_4$. The detection significance is greater or equal to single-instrument retrievals. Both missions provide specific information to characterize a terrestrial habitable exoplanet, but the scientific yield is maximized with synergistic UV/VIS/NIR+MIR observations. Using HWO and LIFE together will provide stronger constraints on biosignatures and life indicators, potentially transforming the search for life in the universe.

16 pages (main text, incl. 12 figures) + appendix; accepted for publication in A&A (current version: post 1st revision). Thirteenth paper of LIFE telescope series

References in corpus (22)

• petitRADTRANS: a Python radiative transfer package for exoplanet characterization and retrieval
• Abiotic Ozone and Oxygen in Atmospheres Similar to Prebiotic Earth
• Large Interferometer For Exoplanets (LIFE): I. Improved exoplanet detection yield estimates for a large mid-infrared space-interferometer mission
• Detecting the Glint of Starlight on the Oceans of Distant Planets
• Disequilibrium biosignatures over Earth history and implications for detecting exoplanet life
• Direct detection of exoplanets in the 3 -- 10 micron range with E-ELT/METIS
• Large Interferometer For Exoplanets (LIFE): V. Diagnostic potential of a mid-infrared space-interferometer for studying Earth analogs
• Large Interferometer For Exoplanets (LIFE): III. Spectral resolution, wavelength range and sensitivity requirements based on atmospheric retrieval analyses of an exo-Earth
• Large Interferometer For Exoplanets (LIFE): II. Signal simulation, signal extraction and fundamental exoplanet parameters from single epoch observations
• Exploring and Validating Exoplanet Atmospheric Retrievals with Solar System Analog Observations
• Is ozone a reliable proxy for molecular oxygen? I. The O2-O3 relationship for Earth-like atmospheres
• Reflected spectroscopy of small exoplanets II: characterization of terrestrial exoplanets
• Exoplanets with ELT-METIS I: Estimating the direct imaging exoplanet yield around stars within 6.5 parsecs
• Large Interferometer For Exoplanets (LIFE): VIII. Where is the phosphine? Observing exoplanetary PH3 with a space based MIR nulling interferometer
• Large Interferometer For Exoplanets (LIFE): IX. Assessing the Impact of Clouds on Atmospheric Retrievals at Mid-Infrared Wavelengths with a Venus-Twin Exoplanet
• Large Interferometer For Exoplanets (LIFE). X. Detectability of currently known exoplanets and synergies with future IR/O/UV reflected-starlight imaging missions
• Inferring Chemical Disequilibrium Biosignatures for Proterozoic Earth-Like Exoplanets
• Transiting exoplanets with the Mid-InfraRed Instrument on board the James Webb Space Telescope: From simulations to observations
• Constraining Background N2 Inventories on Directly Imaged Terrestrial Exoplanets to Rule Out O2 False Positives
• Earth as an Exoplanet. III. Using Empirical Thermal Emission Spectra as an Input for Atmospheric Retrieval of an Earth-twin Exoplanet
• Retrievals Applied To A Decision Tree Framework Can Characterize Earth-like Exoplanet Analogs
• CROCODILE \\ Incorporating medium-resolution spectroscopy of close-in directly imaged exoplanets into atmospheric retrievals via cross-correlation

Cited by in corpus (8)

• Pursuing Truth: Improving Retrievals on Mid-Infrared Exo-Earth Spectra with Physically Motivated Water Abundance Profiles and Cloud Models
• Flow Matching for Atmospheric Retrieval of Exoplanets: Where Reliability meets Adaptive Noise Levels
• Planet Earth in reflected and polarized light: II. Refining contrast estimates for rocky exoplanets with ELT and HWO
• Database of Candidate Targets for the LIFE Mission
• The atmospheres of rocky exoplanets III. Using atmospheric spectra to constrain surface rock composition
• Is Ozone a Reliable Proxy for Molecular Oxygen? II. The impact of N${}_2$O on the O${}_2$-O${}_3$ relationship for Earth-like atmospheres
• Consequences of Non-Gaussian Instrumental Noise in Perturbed Nulling Interferometers
• Retrieving the Red Edge on Earth-like Planets with Heterogeneous Clouds and Surfaces